what happen to my cpu?
only working 1 core?
help!

Either your motherboard chipset or the Hypertransport was overclocked too high, or the SATA clock for that particular socket is not locked-the problem does not appear immediately but takes a while before it can be noticed (more on this below). I had the same problem also-I was lucky the drive could still be read, though with frequent lockups. But it was definitely damaged-testing it on another system revealed numerous read problems even though the drive had never overheated and and no bad sectors.

In the case of an unlocked SATA clock, there is no choice but to try another SATA port. In early K8 days, motherboards were notorious for having unlocked SATA ports, which even a few DFI Lanparty's were plagued with. Sometimes some of the ports are locked, and some are not. If all are not locked, then too bad-the board is going to hold back overclocking or be unstable no matter what.

Here's a problem most overclockers here don't know-none, yes none, of the stability tests we use actually test things other than the CPU, ram, memory controller and graphic core and memory. On AMD's K8 processors (754/939/AM2) its particularly difficult to know if the motherboard chipset is unstable during overclocking until it is severe enough to cause a system lockup because the memory controller (which is usually the first component on an intel CPU-based chipset to give up) for K8 isn't on the motherboard chipset. If the chipset is slightly unstable, say the SATA controller isn't working 100% stable, it won't be obvious until it bungles up a crucial read/write operation(eg windows kernel, or worse, file table/partition table), and the usual non-fatal read/write errors will go unnoticed because of the uncountable bugs found in windows.

And this is only the beginning-the motherboard chipset also controls USB, PCI/PCI-E, LAN, Sound; pretty much everything else other than what the processor, graphics, memory does. Even if the PCI/PCI-E clock is locked, the chipset still is effected because it must relay the data over. So you can't say the chipset is 100% stable until you can be sure that all the motherboard functions work 100%, which to my knowledge is a pain to check everything.

About your data, I'm sorry to say this-if the partitions have disappeared it will probably not be possible to recover it without substantial effort (especially if you have done any write operations on the disk since the disaster). I personally have had to deal with 120+160+120+160+80GB worth of data recovery, and even with professional help I can tell you it wasn't easy nor was it a complete recovery.

To all overclockers, if this is discouraging-keep this in mind. If you keep backups and are willing to put up with occational system lock ups, overclocking is still rewarding-we are getting high end performance out of cheap stuff, in some cases even getting performance money alone can't buy  . Not to mention all the fun we've had tweaking everything to perfection